Editing Elementary particle (section)

==== Mass ====
The following table lists current measured masses and mass estimates for all the fermions, using the same scale of measure: [[Electronvolt|millions of electron-volts]] relative to square of light speed (MeV/''c''<sup>2</sup>). For example, the most accurately known quark mass is of the top quark ({{Subatomic particle|top quark}}) at {{val|172.7|ul=GeV/c2}}, estimated using the [[on-shell scheme]].

{| class="wikitable" style="margin:0 0 1em 1em;"
|+ Current values for elementary fermion masses
|-
! Particle symbol
! Particle name
! Mass value
! Quark mass estimation scheme (point)
|-
| {{math|{{Subatomic particle|electron neutrino}}}}, {{math|{{Subatomic particle|muon neutrino}}}}, {{math|{{Subatomic particle|tauon neutrino}}}}
| [[Neutrino]]<br />(any&nbsp;type)
| style="text-align:right;" | < {{val|2|ul=eV/c2}}<ref>{{cite journal |last1=Tanabashi |first1=M. |last2=Hagiwara |first2=K. |last3=Hikasa |first3=K. |last4=Nakamura |first4=K. |last5=Sumino |first5=Y. |last6=Takahashi |first6=F. |last7=Tanaka |first7=J. |last8=Agashe |first8=K. |last9=Aielli |first9=G. |last10=Amsler |first10=C. |display-authors=6 |collaboration=Particle Data Group |title=Review of Particle Physics |journal=[[Physical Review D]] |volume=98 |issue=3 |date=2018-08-17 |page=030001 |df=dmy-all |doi=10.1103/physrevd.98.030001 |bibcode=2018PhRvD..98c0001T |pmid=10020536 |doi-access=free|hdl=10044/1/68623 |hdl-access=free }}</ref>
|
|-
| {{Subatomic particle|electron}}
| [[electron]]
| style="text-align:right;" | {{val|0.511|ul=MeV/c2}}
|
|-
| {{Subatomic particle|up quark}}
| [[up quark]]
| style="text-align:right;" | {{val|1.9|ul=MeV/c2}}
| [[MSbar scheme]] ({{mvar|μ}}<sub>{{overline|MS}}</sub> = {{val|2|u=GeV}})
|-
| {{Subatomic particle|down quark}}
| [[down quark]]
| style="text-align:right;" | {{val|4.4|ul=MeV/c2}}
| [[MSbar scheme]] ({{mvar|μ}}<sub>{{overline|MS}}</sub> = {{val|2|u=GeV}})
|-
| {{Subatomic particle|strange quark}}
| [[strange quark]]
| style="text-align:right;" | {{val|87|u=MeV/c2}}
| [[MSbar scheme]] ({{mvar|μ}}<sub>{{overline|MS}}</sub> = {{val|2|u=GeV}})
|-
| {{math|{{Subatomic particle|muon}}}}
| [[muon]]<br />([[mu lepton]])
| style="text-align:right;" | {{val|105.7|ul=MeV/c2}}
|
|-
| {{Subatomic particle|charm quark}}
| [[charm quark]]
| style="text-align:right;" | {{val|1320|ul=MeV/c2}}
| [[MSbar scheme]] ({{mvar|μ}}<sub>{{overline|MS}}</sub> = {{mvar|m}}<sub>c</sub>)
|-
| {{math|{{Subatomic particle|tau}}}}
| [[tauon]] ([[tau&nbsp;lepton]])
| style="text-align:right;" | {{val|1780|ul=MeV/c2}}
|
|-
| {{Subatomic particle|bottom quark}}
| [[bottom quark]]
| style="text-align:right;" | {{val|4240|ul=MeV/c2}}
| [[MSbar scheme]] ({{mvar|μ}}<sub>{{overline|MS}}</sub> = {{mvar|m}}<sub>b</sub>)
|-
| {{Subatomic particle|top quark}}
| [[top quark]]
| style="text-align:right;" | {{val|172700|ul=MeV/c2}}
| [[On-shell scheme]]
|}

Estimates of the values of quark masses depend on the version of [[quantum chromodynamics]] used to describe quark interactions. Quarks are always confined in an envelope of [[gluon]]s that confer vastly greater mass to the [[meson]]s and [[baryon]]s where quarks occur, so values for quark masses cannot be measured directly. Since their masses are so small compared to the effective mass of the surrounding gluons, slight differences in the calculation make large differences in the masses.